Design And Dynamics Characteristics Of TBM Reducer In Confined Space

With the rapid development of urbanization process in our country, as well as transportation, hydraulic engineering and other infrastructure, especially the huge demand for underground road traffic in the city, tunnel boring equipment and technology has been widely used. In recent years, research on the tunnel boring machine and key technology has been strengthened further and reducer, as the key components for the drive system of TBM cutterhead, is faced with technical requirements such as large transmission ratio, high transfer efficiency and strong bearing ability in limited space. Therefore, it is increasingly necessary to design a kind of reducer structure, which has good dynamic characteristic and meets the technical requirements above.In this paper, based on structural topology optimization, the complete optimization process, ranging from the basic structure, topology evolution, comprehensive judgment, topological inverse topology optimization to the optimized structure selection, is established as well as bond graph model of Planetary Gear Train for the reducer to analyze reducer dynamic characteristics and the influence law of main parameters. The main contents are as follows:(1) The epicyclic gear train topology optimization theory based on function distribution is described and the complete optimization process, ranging from the basic structure, topology evolution, comprehensive judgment, topological inverse topology optimization to the optimized structure selection, is established, improving a planetary gear train topology optimization method.(2) Parameter constraint condition including the number of gears, the degree of freedom is set and optimum schemes are finally obtained by employing isomorphism detection, enclosed power flow detection and shorter path detection as well as study on transmission characteristics of typical structure belonging to the planetary gear train. The structure for TBM reducer comes to an end, with the help of large transmission ratio, high transfer efficiency and strong bearing ability as the goal.(3) The layout plan for TBM drive system is decided and it is derived that the common ring gear enhances bearing ability through structure features analysis of reducer with planetary gear planetary plus enclosed mechanism and form of primary, flow and distribution of power become clear through transmission characteristics analysis. The optimal parameters for reducer system are gotten by the use of MATLAB as optimization tool, through the volume minimum as the goal and establishment of a series of constraints, including tooth number constraint, fatigue strength constraint, geometric constraint.(4) The bond graph theory, basic variables, the introduction of basic icons and causality during the process of modeling are described. A bond graph model of gear pair is established to get the derivation of its state equation and the representation of the important parameters, such as friction, transmission error, meshing stiffness, damping, laying a theoretical foundation for modeling of planetary gear train and the whole gear system by bond graph theory.(5) The reducer is divided into planetary gear train and enclosed mechanism from the structural characteristics and two parts were established bond graph models respectively to find out whether the factor generates a impact on the system response by establishment of a different models and its influence law affects by choosing different parameter values meanwhile.